Age at time of hepatitis Be antibody seroconversion in childhood chronic hepatitis B infection and mutant viral strain detection rates

CTL-associated and NK cell-associated immune responses induce different HBV DNA reduction patterns in chronic hepatitis B patients

The activation of hepatitis B virus (HBV)-related hepatitis is associated with both natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). We analyzed the association between the immune response and changes in the proportion of Pre-S deletion variants. We quantified Pre-S deleted HBV (HBV-del) and wild-type HBV (HBV-wt) DNA levels in sera obtained from HBV-infected mice and chronic hepatitis B patients. In chronic hepatitis B patients, the HBV-del proportion usually increased during or after ALT elevation but did not occur during all ALT elevations. To clarify this difference in the immunological responses, we performed in vivo analyses using HBV-infected human hepatocyte chimeric mice. Although HBV-del proportions did not change in mice with NK cell-associated hepatitis or in mice treated with entecavir, the proportions sharply increased in mice with CTL-associated hepatitis. Furthermore, the number of patients in which HBV-del proportions were greater than 5% was significantly higher in chronic hepatitis B patients than in asymptomatic carriers (P = 0.023). We identified associations between virological response in chronic hepatitis B patients and two different immune responses. The proportion of HBV-del variants could be a useful biomarker for distinguishing between chronic hepatitis and asymptomatic carriers.

Safety, immunization coverage and determinants of a new kind of Hepatitis B vaccine firstly applied in Ningbo, China

Evaluate safety and immunization coverage of a new kind of recombinant Hepatitis B vaccine (HepB) in Ningbo city, China. Two groups were carried out in 2 of 11 randomly selected countries in Ningbo in 2009. All of the infants born from July 1 to December 31, 2009 were enrolled as subjects and received 3 doses of HepB at 0, 1, 6 month. Control group (N = 3452) received current HepB derived from Saccharomyces Cerevisiae Yeast (HepB made by recombinant DNA techniques in Saccharomyces Cerevisiae Yeast, HepB-SCY; 5 μg/0.5 ml per dose) and experimental group (N = 5104) received the new kind of HepB derived from Hansenula polymorpha Yeast (HepB made by recombinant DNA techniques in Hansenula polymorpha Yeast, HepB-HPY; 10 μg/0.5 ml per dose). 3-dose and timely birth dose (TBD) coverage were available and compared between 2 groups. Standard structured questionnaires were applied to record information from parents and hospitals for selecting determinants of coverage. The data were analyzed using stepwise multiple logistic regression models. After each dose, HepB-related adverse events (AEs) and recta-temperature were recorded for 7 days. 3-dose coverage in control group (89.98%) was higher than that in experimental group (χ2 = 575.1173, P < 0.0001). TBD coverage in control and experimental group were 98.41% and 98.53%, respectively. No statistically significant difference in TBD coverage was found between 2 groups (χ2 = 0.0623, P = 0.8029). A total of 9 local AEs were reported, 4 for control group and 5 for experimental group. The percentages of subjects reporting AEs were similar across the 2 vaccination groups. No serious or immediate reactions were found in this study. From logistic models, receiving 10 μg vaccine (odds ratio [OR]:0.38; 95% confidence interval [95%CI]: 0.34-0.44) and mother migrating from other cities (OR: 0.45; 95%CI: 0.42-0.47) were the determinants for non-acceptance of 3 doses of HepB; infants born from low grade hospitals and native mothers contributed to administrate the TBD.

New perspective on the natural course of chronic HBV infection

Chronic hepatitis B virus (HBV) infection is a significant threat to public health and an enormous burden on society. Mechanisms responsible for chronic HBV infection remain poorly understood. A better understanding of the natural course of chronic HBV infection may shed new light on the mechanisms underlying this disease and help in designing new antiviral strategies. Natural course of chronic HBV infection is conventionally viewed as an uninterrupted process that is usually marked by HBV e antigen (HBeAg) seroconversion or characterized by different phases associated with assumed host responses to HBV infection. However, none of these descriptions captures or highlights the core events that determine the natural course of chronic HBV infection. In this review, we briefly present the current knowledge on this subject and explain the significance and implication of events that occur during infection. A pre-core mutant becomes predominant in the viral population following elimination of the wild-type virus in duck hepatitis B virus-chronically infected animals. The coupled events in which first there is viral clearance that clears wild-type virus and then there is the reinfection of wild-type virus cleared livers with mutant virus are highly relevant to understanding of the natural course of chronic HBV infection under both treated and untreated conditions. In our new perspective, a general natural course of chronic HBV infection comprises cycles of viral clearance and reinfection, and such cycles prolong the chronic HBV infection course. Reviewing published data on the natural course of chronic HBV infection can reduce the possibility of missing important points in the initial data interpretation.

HBx protein is indispensable for development of viraemia in human hepatocyte chimeric mice

The non-structural X protein, HBx, of hepatitis B virus (HBV) is assumed to play an important role in HBV replication. Woodchuck hepatitis virus X protein is indispensable for virus replication, but the duck hepatitis B virus X protein is not. In this study, we investigated whether the HBx protein is indispensable for HBV replication in vivo using human hepatocyte chimeric mice. HBx-deficient (HBx-def) HBV was generated in HepG2 cells by transfection with an overlength HBV genome. Human hepatocyte chimeric mice were infected with HBx-def HBV with or without hepatic HBx expression by hydrodynamic injection of HBx expression plasmids. Serum virus levels and HBV sequences were determined with mice sera. The generated HBx-def HBV peaked in the sucrose density gradient at points equivalent to the generated HBV wild type and the virus in a patient's serum. HBx-def HBV-injected mice developed measurable viraemia only in continuously HBx-expressed liver. HBV DNA in the mouse serum increased up to 9 log(10) copies ml(-1) and the viraemia persisted for more than 2 months. Strikingly, all revertant viruses had nucleotide substitutions that enabled the virus to produce the HBx protein. It was concluded that the HBx protein is indispensable for HBV replication and could be a target for antiviral therapy.

Hepatitis B: epidemiological, immunological, and serological considerations emphasizing mutation

The global prevalence of hepatitis B virus is estimated to be 350 million chronic carriers, varying widely from low (<2%, as in Western Europe, North America, New Zealand, Australia, and Japan) to high (>8% as in Africa, Southeast Asia, and China). The overall prevalence in Brazil is about 8%. There are currently 7 genotypic variations, from A to G, and also 4 main surface antigen subtypes: adw, ayw, adr, and ayr. There has been great interest in identifying the geographic distribution and prognosis associated with the various genotypes and subtypes. Although the serologic test is highly sensitive and specific, it does not detect cases of mutant hepatitis B, which is increasingly common worldwide due to resistance and vaccine escape, antiviral therapy, and immunosuppression, among other causes. Alterations in surface, polymerase, X region, core, and precore genes have been described. The main mutations occur in surface and in core/precore genes, also known as occult hepatitis, since its serologic markers of active infection (HBsAg) and viral replication (HBeAg) can be negative. Thus, mutation should be suspected when serologic tests to hepatitis B show control of immunity or replication coincident with worsened clinical status and exclusion of other causes of hepatitis.